Continuous Presence (Cp) Conferencing - Polycom RMX 1500 Administrator's Manual

Chapter 2-Additional Conferencing Information

Continuous Presence (CP) Conferencing

Video Resolutions in CP
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Video quality in Continuous Presence mode is affected by the conference
line rate (that determines the maximum line rate to be used by the
connecting endpoints), and the video capabilities of the endpoints such as
the video protocol, video resolution and frame rate.
The video protocol selected by the system determines the video
compression standard used by the endpoints. In Continuous Presence
conferences, the system selects the best video protocol for the endpoint
according to its capabilities.
The following Video protocols are supported:
• H.261 - the video compression algorithm mandatory to all endpoints.
It is used by endpoints that do not support other protocols.
• H.263 - a video compression algorithm that provides a better video
quality than H.261. This standard is not supported by all endpoints.
• H.264 - a video compression standard that offers improved video
quality, especially at line rates lower than 384 Kbps.
H.264 High Profile allows higher quality video to be transmitted at
lower bit rates.
• RTV - a video protocol that provides high quality video conferencing
capability to Microsoft OCS (Office Communicator Server) endpoints at
resolutions up to HD720p30. (SIP only).
The RMX always attempts to connect to endpoints at the highest line rate.
If the connection cannot be established, the RMX attempts to connect at
the next highest line rate at its highest supported resolution.
Depending on the line rate, the RMX sends video at the best possible
resolution supported by the endpoint regardless of the resolution
received from the endpoint.
The video resolution is also defined by the Quality settings:
• Motion, when selected, results lower video resolution.
• Sharpness, when selected, sends higher video resolution.
The combination of frame rate and resolution affects the number of video
resources required on the MCU to support the call.